Photosynthesis
Photosynthesis is how plants use light, water, and air to make their own food and grow.
A leaf works like a kitchen mixing bowl that runs on sunlight. Water soaks up from the roots into the bowl. Air flows in and adds carbon dioxide. Sunlight hits the bowl and fuses the water and air into sugar, which the plant eats as food.
Explaining photosynthesis by grade level
Plants need light to make their food. That is why a plant near a fish tank can grow so well. The fish breathe out a gas that helps the plant. The plant takes in that gas, plus light and water, to feed itself.
Projects that explore photosynthesis
Without sunlight, photosynthesis cannot run — and leaves show it. You clip cardboard shapes onto leaves of a living plant, blocking sunlight from reaching those sections. After four days, the covered spots look different from the rest of the leaf.
Green chlorophyll powers photosynthesis, but it also hides other colors in a leaf all summer long. When chlorophyll breaks down in fall, those hidden pigments finally show through — the reds and yellows of autumn.
Carbon dioxide from the air is a key ingredient in photosynthesis. Goldfish produce carbon dioxide that nearby plants can absorb. This experiment tests whether Elodea plants grow faster with more fish providing that ingredient.